Usage:
set_difference(minuend.begin(), minuend.end(),
subtracter.begin(), subtracter.end(), difference.begin());
The source code of set_difference() from <stl_algo.h>:
/**
* @brief Return the difference of two sorted ranges.
* @ingroup set_algorithms
* @param __first1 Start of first range.
* @param __last1 End of first range.
* @param __first2 Start of second range.
* @param __last2 End of second range.
* @return End of the output range.
* @ingroup set_algorithms
*
* This operation iterates over both ranges, copying elements present in
* the first range but not the second in order to the output range.
* Iterators increment for each range. When the current element of the
* first range is less than the second, that element is copied and the
* iterator advances. If the current element of the second range is less,
* the iterator advances, but no element is copied. If an element is
* contained in both ranges, no elements are copied and both ranges
* advance. The output range may not overlap either input range.
*/
template<typename _InputIterator1, typename _InputIterator2,
typename _OutputIterator>
inline _OutputIterator
set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2,
_OutputIterator __result) {
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept < _InputIterator1 >)
__glibcxx_function_requires(_InputIteratorConcept < _InputIterator2 >)
__glibcxx_function_requires(_OutputIteratorConcept < _OutputIterator,
typename iterator_traits<_InputIterator1>::value_type >)
__glibcxx_function_requires(_LessThanOpConcept <
typename iterator_traits<_InputIterator1>::value_type,
typename iterator_traits<_InputIterator2>::value_type >)
__glibcxx_function_requires(_LessThanOpConcept <
typename iterator_traits<_InputIterator2>::value_type,
typename iterator_traits<_InputIterator1>::value_type >)
__glibcxx_requires_sorted_set(__first1, __last1, __first2);
__glibcxx_requires_sorted_set(__first2, __last2, __first1);
return _GLIBCXX_STD_A::__set_difference(__first1, __last1,
__first2, __last2, __result,
__gnu_cxx::__ops::__iter_less_iter());
}The source code of __set_difference() from <stl_algo.h>:
template<typename _InputIterator1, typename _InputIterator2,
typename _OutputIterator,
typename _Compare>
_OutputIterator
__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2,
_OutputIterator __result, _Compare __comp) {
while (__first1 != __last1 && __first2 != __last2)
if (__comp(__first1, __first2)) {
*__result = *__first1;
++__first1;
++__result;
}
else if (__comp(__first2, __first1))
++__first2;
else {
++__first1;
++__first2;
}
return std::copy(__first1, __last1, __result);
}